As a metal continuous casting method, a properzi method is known. In this method, a casting space is formed between a groove formed on a peripheral surface of a casting wheel and an endless belt fitted on the groove. Molten metal is supplied to the casting space when the casting wheel and the endless belt are rotating to continuously manufacture a cast member. In such a continuous casting method, the casting wheel and the endless belt are cooled, and therefore the molten metal supplied to the casting space will be gradually solidified from the entire circumference thereof toward the central portion thereof (see, e.g., Japanese Unexamined Laid-open Patent Publication No. S53-123332 and Japanese Unexamined Laid-open Patent Publication No. S59-193737).
In the aforementioned continuous casting method, the final solidification portion will be positioned at the central portion of the cast member, and therefore shrinkage cavities and/or breakages tend to be generated at the central portion due to the solidification shrinkage. Accordingly, in the cast member having such defects, even if the cast member is subjected to plastic working such as rolling, extruding or drawing, the end product will contain the cast defects.
The aforementioned Japanese Unexamined Laid-open Patent Publication No. S53-123332 discloses that the casting wheel and the endless belt are held at 40 to 200 ° C. to avoid quick cooling of the cast member to thereby prevent the cast cracking. In this method, however, although cracking of the contact portion of the cast member contacting the casting wheel and/or the endless belt can be prevented, the shrinkage cavities and/or breakages in the final solidification portion cannot be prevented. Furthermore, although cast defects generated at the surface of the cast member can be disappeared or reduced by the following plastic working, cast defects generated at the central portion will not be dissolved. Furthermore, if cast defects exist at the central portion of the cast member or worked article, they cannot be removed by scalping or peeling processing.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.